WO 99/14871 discloses a simple block coding arrangement in which symbols are transmitted over a plurality of transmit channels, in connection with coding that comprises only of simple arithmetic operations, such as negation and conjugation. The diversity created by the transmitter utilizes space diversity and either time or frequency diversity. Space diversity is effected by redundantly transmitting over a plurality of antennas, time diversity is effected by redundantly transmitting at different times, and frequency diversity is effected by redundantly transmitting at different frequencies. Illustratively, using two transmit antennas and a single receive antenna, one of the disclosed embodiments provides the same diversity gain as the maximal-ratio receiver combining (MRRC) scheme with one transmit antenna and two receive antennas.
The coding scheme disclosed in WO 99/14871 is known in the art as Alamouti coding scheme and has also been described in S. M. Alamouti “A simple transmit diversity technique for wireless communications”, IEEE J. Sel. Areas. Comm. vol. 16, pp. 1451-1458, October 1998.